Baxi/potterton 105 he rad problem??

[sparky3366]

Heres one for you...my elderly parents have a baxi 105 he fitted in their rented bungalow. It is about 4 years old and has been in the place since it was built. Why do they have to manually turn off all the trv's to prevent the rads getting hot even when the heating is turned off at the boiler? There have been a few issues with the electrical and plumbing that weren't picked up on the build snagging but they were all resolved...its a horstmann stat in the hall way btw.

 

[SimonJohns]

Sounds like they either haven't got a thermostat or a clock. Maybe even faulty clock

 

[sparky3366]

horstmann stat in the hall, why do the rads get hot even when the heating is turned off?

 

[SimonJohns]

They can't or shouldn't.

I would be looking at controls. Clock etc. I don't know if this boiler has a water preheat. If it does it may be a faulty dv

 

[Billy Bob Bob]

if its turned to water only on the boiler do the rads get hot?

 

[sparky3366]

yess they do...

 

[Billy Bob Bob]

you have a blocked plate heat exchanger or a faulty diverter valve

 

[sparky3366]

this forum is great...they've had countless sparks & plumbers there and nobody could find anything. Been like that since it was fitted...cheers gas man

 

[Shefflad]

I've just fixed my girlfriend's 105 that had an issue for 2 years that even a gas safe heating engineer missed. Hers was doing kind of the opposite - the boiler would fire up, heat the rads, but when the stat clicked the burner off it'd lockout with a low pressure / pump failure. When reset it'd work again until the stat click off again.

It was a stuck pin on the diverter valve - when the pump clicked off after overrun the pin stayed up, A quick tease with a toothbrush and a squirt of silicon lube and it was free, and works perfect now. 🙂

Have a look and see if both pins are free on the diverter - front one is HW, rear vertical one is CH. They move out with demand, and return closed when off.